Bronco L6-300 4.9L VIN Y 1-bbl (1983)
Ignition Timing Connector: Description and Operation
Fig. 20 Ignition Timing Vacuum Switch
Below vacuum setting, this switch, Fig. 20, used on some vehicles, is open and signals the ignition module to retard spark timing. The switch is closed
above the vacuum setting and the ignition module is in the non-retard spark timing mode. Calibration resistors inside the switch control the amount of
retard.
